10. Scalp Stimulant/Hair Revitalizer

Why they fight the aging process: A head of thick, lustrous hair signifies vitality. Products designed to combat thinning hair do so either by stimulating the scalp to encourage hair growth or by improving the quality of the hair you still have so that it appears fuller and more abundant. Either way, these products make the most of the mane you have, particularly if you're in the early stages of hair loss.

How to use them: The frequency with which you'll need to a use hair-growth treatment will vary from product to product. You'll almost certainly require more than one application, however, and you'll have use the product regularly to maintain its results.